Flexible display

ABSTRACT

A flexible display is disclosed. In one aspect, the flexible display includes a window layer including a bending area and a non-bending area and a flexible display panel formed over a surface of the window layer and configured to display images. The bending area includes a plurality of cut portions which are configured to be at least partially separated along a plurality of cut lines formed therebetween.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Korean PatentApplication No. 10-2015-0045315 filed in the Korean IntellectualProperty Office on Mar. 31, 2015, the entire contents of which areincorporated herein by reference.

BACKGROUND

1. Field

The described technology generally relates to a flexible display that iscapable of preventing damage caused due to bending of the display, andmaintaining the optical characteristics even when the display is bent.

2. Description of the Related Technology

Currently, widely known display devices, each using a unique displaytechnology, include liquid crystal displays (LCDs), plasma displaypanels (PDPs), organic light-emitting diode (OLED) displays, fieldeffect displays (FEDs), electrophoretic displays (EPDs), and the like.Techniques for forming these types of display devices with flexiblematerial(s) are currently being researched. Since display devices formedwith flexible material(s) can be used to develop new devices such aselectronic books and electronic paper, these flexible displays areanticipated to be widely used for various applications.

However, since such flexible displays have a structure in which severallayers are stacked, stress is not evenly distributed when the displaysare bent due to the differences in the elastic coefficients of thematerials forming respective layers and the differences in theproperties of components contained in each layer. Since stress that isnot evenly distributed is concentrated in one area, it may experiencepremature wear, resulting in damage or complete failure. Accordingly,flexible displays having a structure that more evenly distribute stresswhen bent is desired.

The above information disclosed in this Background section is onlyintended to facilitate the understanding of the background of thedescribed technology and therefore it may contain information that doesnot form the prior art that is already known in this country to a personof ordinary skill in the art.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One inventive aspect is a flexible display that is capable of preventingdamage caused due to bending of the display, and maintaining the opticalcharacteristics even when bent.

Further, aspects are not limited to the aforementioned aspects, andother aspects not mentioned herein will be understood by those skilledin the art from the description below.

Another aspect is a flexible display, including a window layer thatincludes a bent area and a non-bending area and a flexible display panelformed on one surface of the window layer to display an image, whereinthe bent area can include a plurality of cut units formed by the windowlayer being cut into a plurality.

The flexible display can further include a hard coating layer formed onthe other surface of the window layer and an adhesive layer interposedbetween the window layer and the hard coating layer so that one end ofthe cut unit slips along a surface of the adhesive layer, wherein oneend of one of the plurality of cut units can be slipped along thesurface of the adhesive layer to be spaced apart from an adjacent one ofthe plurality of the cut units.

The flexible display panel can include a display area including a pixelfrom which light is emitted to display an image, and a non-display areain which light is blocked not to display an image, wherein thenon-bending area can be formed at a position corresponding to thedisplay area, and the bent area can be formed at a positioncorresponding to the non-display area.

Another aspect is a flexible display, including a window layer thatincludes a bent area and a non-bending area, and a flexible displaypanel formed on one surface of the window layer and including anemission area where light emitted from a unit pixel passes through todisplay an image, wherein the bent area can be formed by partiallyremoving the window layer.

The bent area can include a plurality of protrusions formed by partiallyremoving the window layer to have a larger cross-section than that ofthe emission area at a position corresponding to the emission area, anda bent area filling portion that fills the bent area so that a height ofthe bent area is equal to a surface of the window layer.

The bent area filling portion can be made with transparent syntheticresins or glass.

The flexible display can further include a hard coating layer formedwith the same material as the bent area filling portion, and can beformed on the other surface of the window layer.

The bent area can include a plurality of grooves formed by partiallyremoving the window layer corresponding to the emission area to have alarger cross-section than that of the emission area while correspondingto a shape of the emission area.

The flexible display can further include a hard coating layer formed onthe other surface of the window layer and formed with transparentsynthetic resins or glass.

The grooves can be filled with the same material as the hard coatinglayer.

Another aspect is a flexible display comprising a window layer includinga bending area and a non-bending area; and a flexible display panelformed over a surface of the window layer and configured to displayimages, wherein the bending area includes a plurality of cut portionswhich are configured to be at least partially separated along aplurality of cut lines formed therebetween.

In exemplary embodiments, the flexible display further comprises a hardcoating layer formed over another surface of the window layer so as tooppose the flexible display panel; and an adhesive layer interposedbetween the window layer and the hard coating layer, wherein an end ofeach of the cut portions is configured to slip along a surface of theadhesive layer as the flexible display is bent. The ends of the cutportions can be further configured to slip along the surface of theadhesive layer so as to be spaced apart from each other.

In exemplary embodiments, flexible display panel can include a displayarea including at least one pixel configured to emit light so as todisplay an image; and a non-display area, wherein the non-bending areais arranged at a position corresponding to the display area, and whereinthe bent area is arranged at a position corresponding to the non-displayarea. The cut portions can be directly connected along the surface ofthe flexible display panel.

Another aspect is a flexible display, comprising a window layerincluding a bending area and a non-bending area; and a flexible displaypanel formed over a surface of the window layer and including aplurality of emission areas configured to emit light to display animage, wherein at least a portion of the window layer is removed fromthe bent area.

In exemplary embodiments, the bent area includes a plurality ofprotrusions, each having a greater cross-section than that of theemission area, wherein the protrusions are arranged at positionscorresponding to the emission areas; and a filler formed over theprotrusions such that the height of the bending area is substantiallyequal to that of the window layer. The filler can comprise transparentsynthetic resins or glass. The flexible display can further comprise ahard coating layer formed of the same material as the filler and formedover another surface of the window layer so as to oppose the flexibledisplay panel..

In exemplary embodiments, the bent area includes a plurality of groovesarranged at positions corresponding to the emission areas, wherein eachof the grooves has a cross-section that is greater than that of theemission areas. The flexible display can further comprise a hard coatinglayer formed on another surface of the window layer so as to oppose theflexible display panel, wherein the hard coating layer is formed oftransparent synthetic resins or glass. A filler comprising the samematerial as the hard coating layer can fill in the grooves.

According to at least one embodiment, even though a flexible display isbent, since stress due to the bending can be properly dispersed, it ispossible to prevent the flexible display from being damaged and tomaintain the optical characteristics thereof when bent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a flexible display according to anexemplary embodiment.

FIG. 2 is a drawing illustrating a configuration in which the flexibledisplay of FIG. 1 is bent.

FIG. 3 is a partial cross-sectional view of a flexible display accordingto a first exemplary embodiment taken along line II-II of FIG. 1.

FIG. 4 is a drawing illustrating a configuration in which the flexibledisplay of FIG. 3 is bent.

FIG. 5 is a partial cross-sectional view of a flexible display accordingto a second exemplary embodiment taken along line II-II of FIG. 1.

FIG. 6 is a drawing illustrating a configuration in which the flexibledisplay of FIG. 5 is bent.

FIG. 7 is a partial cross-sectional view of a flexible display accordingto a third exemplary embodiment taken along line II-II of FIG. 1.

FIG. 8 is a drawing illustrating a configuration in which the flexibledisplay of FIG. 7 is bent.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Hereinafter, exemplary embodiments will be described in detail withreference to the accompanying drawings. However, in describing theembodiments, a description of known functions or configurations will beomitted such that the description of the subject matter is clear.

The drawings and description are to be regarded as illustrative innature and not restrictive. Like reference numerals designate likeelements throughout the specification. In addition, the size andthickness of each component shown in the drawings may be exaggerated forthe sake of clarity and ease of description, but the describedtechnology is not limited thereto.

It will be understood that when an element such as a layer, film,region, or substrate is referred to as being “on” another element, itcan be directly on the other element or intervening elements may also bepresent.

FIG. 1 is a perspective view of a flexible display according to anexemplary embodiment. FIG. 2 is a drawing illustrating a configurationin which the flexible display of FIG. 1 is bent.

As shown FIGS. 1 and 2, the flexible display 100 according to anexemplary embodiment includes a window layer 110, a flexible displaypanel 120, and a hard coating layer 130. In the flexible display 100according to the present exemplary embodiment, the window layer 110 isformed on the outermost side of the flexible display 100 to block andprotect the interior thereof.

Since the flexible display 100 can be bent, the window layer 110according to the present exemplary embodiment can be formed of aflexible material to be bent together with the flexible display 100.Further, the window layer 110 can be formed of an electricallyinsulating material to electrically insulate the interior of theflexible display 100. The window layer 110 can be formed of atransparent material to allow light generated from the flexible displaypanel 120 to be emitted the exterior of the flexible display 100. Morespecifically, the window layer 110 according to the present exemplaryembodiment can be formed of a material such glass and/or plastic, but itis not limited thereto, and any material having such aforementionedcharacteristics can be used as a material for forming the window layer110 of the present exemplary embodiment.

As shown in FIG. 1, the window layer 110 can be divided into a bent areaor flexible area (BD) and a non-bending area (FL). However, since thebent area (BD) and the non-bending area (FL) are shown as being dividedto illustrate and explain a configuration in which the flexible display100 shown in FIG. 2 can be bent, they may not be visually different whenthe flexible display 100 is unfolded. That is, the bent area (BD) andthe non-bending area (FL) can be visually indistinguishable to a user ofthe flexible display 100.

Further, the division between the bent area (BD) and the non-bendingarea (FL) is not necessarily fixed, and thus the position of thedivision can vary according to the region at which the flexible display100 is bent.

As shown in FIG. 2, the bent area (BD) is an area substantially deformedwhen the flexible display 100 is bent, and the non-bending area (FL) isan area that is not deformed and remains flat even when the flexibledisplay 100 is bent. The flexible display panel 120 can generate lightin order to display an image by the flexible display 100 according tothe present exemplary embodiment. The flexible display panel can beformed on one surface of the window layer 110 according to the presentexemplary embodiment.

The flexible display panel 120 of the present exemplary embodiment canemploy any one of various display techniques, such as a liquid crystaldisplay (LCD) panel, a plasma display panel (PDP), an organiclight-emitting diode (OLED) display panel, or the like, according to thestructure and light generation technique, but it is not limited thereto.In addition, the flexible display panel 120 of the present exemplaryembodiment can be formed of a flexible material such as plastic to beeasily bent.

The hard coating layer 130 is formed on the window layer 110 to protectthe window layer 110 according to the present exemplary embodiment.Therefore, as shown in FIG. 1, the flexible display panel 120 can beformed on the one surface of the window layer 110, and the hard coatinglayer 130 can be formed on an opposing surface of the window layer 110.The hard coating layer 130 is illustrated in FIGS. 1 and 2, but it maybe omitted in some embodiments. The hard coating layer 130 can also beformed of a flexible material so that the flexible display 100 of thepresent exemplary embodiment can be smoothly or easily bent andunfolded.

The bent area (BD) and the non-bending area (FL) formed on the windowlayer 110 can be formed to have a discontinuous structure. The term“discontinuous structure” generally means that the arrangement orconfiguration of the bent and non-bending areas (BD) and (FL) aredifferent from each other. Therefore, the bent area (BD) and thenon-bending area (FL) can be different from each other in theirarrangement and/or configuration, and they can vary according to theposition at which the flexible display 100 is bent, as described above.

A detailed structural difference between the bent area (BD) and thenon-bending area (FL) according to first to third exemplary embodimentswill be described in detail with reference to FIGS. 3 to 8. FIG. 3 is apartial cross-sectional view of a flexible display 100 according to afirst exemplary embodiment taken along line II-II of FIG. 1. FIG. 4 is adrawing illustrating a configuration in which the flexible display 100of FIG. 3 is bent. FIG. 5 is a partial cross-sectional view of aflexible display 100 according to a second exemplary embodiment takenalong line II-II of FIG. 1. FIG. 6 is a drawing illustrating aconfiguration in which the flexible display 100 of FIG. 5 is bent. FIG.7 is a partial cross-sectional view of a flexible display 100 accordingto a third exemplary embodiment taken along line II-II of FIG. 1. FIG. 8is a drawing illustrating a configuration in which the flexible display100 of FIG. 7 is bent.

The first exemplary embodiment will now be described in detail withreference to FIGS. 3 and 4. As shown in FIGS. 3 and 4, the flexibledisplay 100 according to the first exemplary embodiment includes aplurality of cut units or cut portions 112 formed by some or all of thewindow layer 110 corresponding to the bent area (BD) being cut. The cutunits 112 are formed by some or all of the window layer 110 being cut sothat when the flexible display 100 is bent, the cut units 112 arearranged to be spaced apart from each other so that stress generated dueto the flexible display 100 being bent can be distributed. Further, whenthe flexible display 100 is unfolded, the cut units 112 are arranged tobe adjacent to each other.

Since the window layer 110 can be divided into two areas for each cutmade in the window layer 110, there are a plurality of cut units 112. Alaser cutter can be used for cutting the window layer 110 to form thecut units 112, but is not limited thereto, and any cutter that canprecisely cut some or the all of the window layer 110 for forming a cutline or a slit in the window layer 110 can be used. The cut units 112formed by cutting the window layer 110 according the present exemplaryembodiment can be cut to be parallel to each other in a directionperpendicular to a surface of the window layer 110 to have apredetermined width along a thickness direction of the window layer 110.However, the present exemplary embodiment is not limited thereto, thatis, the scope for implementing the described technology is not limitedto a cut structure for easily bending the flexible display 100.

The flexible display 100 according to the present exemplary embodimentdescribed above can include a hard coating layer 130, and can furtherinclude an adhesive layer 140. The hard coating layer 130 is formed onthe a surface of the window layer 110, and the adhesive layer 140 isinterposed between the window layer 110 and the hard coating layer 130,and one end portion of the cut units 112 can slip along a surface of theadhesive layer 140.

When the flexible display 100 is bent as shown in FIG. 4, the cut unit112 is spaced apart from the adjacent cut unit 112 while one end portionof the cut unit 112 slips along the surface of the adhesive layer 140.Accordingly, when the flexible display 100 is bent, as shown in FIG. 4,a plurality of cut units 112 can be arranged in an arc shape.Additionally, the other end portions of the cut units 112 according tothe present exemplary embodiment can be fixed to the flexible displaypanel 120. The other end portions of the cut units 112 fixed to theflexible display panel 120 maintain the original spacing between theadjacent cut units 112 even when the flexible display 100 is bent.Accordingly, refraction or dispersion of light emitted from the flexibledisplay panel 120 can be reduced or prevented.

Further, the flexible display panel 120 includes a plurality of pixelsthat can emit light, a display area (not shown) in which light emittedfrom the pixels is emitted to the exterior of the flexible display 100to display an image, and a non-display area (not shown) in which lightis blocked in order to not display an image. Accordingly, thenon-bending area (FL) of the present exemplary embodiment can be formedat a position corresponding to the display area, and the bent area (BD)can be formed at a position corresponding to the non-display area. Whenthe bent area (BD) is formed at the position corresponding to thedisplay area, light emitted from the display area can be refracted ordispersed due to the arrangement of the cut units 112 in certainconfigurations. Further, if the bent area (BD) is arranged at theposition corresponding to the display area, problems such as lightleakage may occur.

Accordingly, the bent area (BD) according to the present exemplaryembodiment can be formed at the position corresponding to thenon-display area (NE) to solve the aforementioned problem. Accordingly,the cut units 112 according to the present exemplary embodiment can alsobe formed at a position where an emission area (LE) does not exist(e.g., the non-display area), and thus the non-bending area (FL) can beformed at the position corresponding to the display area. Therefore, aflexible display 100 capable of displaying an image more stably isprovided.

The second and third exemplary embodiments will now be described indetail with reference to FIGS. 5 to 8. FIGS. 5 and 6 illustrate aflexible display 100 in which a plurality of protrusions 114 are formedin a bent area (BD) according to the second exemplary embodiment. FIGS.7 and 8 illustrate a flexible display 100 in which a plurality ofgrooves 116 are formed in a bent area (BD) according to the thirdexemplary embodiment.

As shown in FIGS. 5 and 6, the flexible display 100 in which theprotrusions 114 are formed includes a window layer 110 and a flexibledisplay panel 120 including the bent area (BD) and a non-bending area(FL). Since the window layer 110 and the flexible display panel 120 ofthe present exemplary embodiment correspond to those described above, adetailed description of such will be omitted. In the embodiment of FIGS.5 and 6, the flexible display panel 120 can include an emission area(LE) through which light emitted from a unit pixel passes. In otherwords, the flexible display panel 120 includes the emission area (LE) inwhich an area of the flexible display panel 120 corresponding to theunit pixel is formed.

The bent area (BD) of the present exemplary embodiment is formed bypartially removing the window layer 110. More specifically, as shown inFIGS. 5 and 6, the bent area (BD) is formed by removing an area of thewindow layer 110, other than an area of the window layer 110corresponding to the protrusions 114, so that the protrusions 114 havinga greater cross-section than that of the emission area (LE) of theflexible display panel 120 can be formed. For example, as shown in FIGS.5 and 6, the width W1 of the protrusions can be greater than the widthW2 of the emission areas (LE). In other words, the bent area (BD) of thepresent exemplary embodiment is formed by removing the window layer 110so that the protrusions 114 remain after the removal.

As in the present exemplary embodiment, when the cross-section of theprotrusion 114 is greater than that of the emission area (LE), lightemitted from the emission area (LE) can be directly emitted withoutbeing refracted or dispersed. Accordingly, even when the flexibledisplay 100 is bent, the optical characteristics thereof can beprevented from deteriorating. The protrusions 114 of the presentexemplary embodiment can be formed to have substantially the same heightas the thickness of the window layer 110, but they is not limitedthereto, and the protrusions 114 can be formed to have height that isless than the thickness of the window layer 110. In addition, the bentarea (BD) can be formed to have a shape as shown in FIGS. 5 and 6 byleaving a portion of the window layer 110 after removing some of thewindow layer 110 so that a lower portion of the protrusions 114 can beconnected to the window layer 110.

A bent area filling portion or filler 132 is formed on a surface of theremoved window layer 110. The bent area filling portion 132 is formed byfilling the bent area (BD) so that the removed area of the window layer110 may have substantially the same height and width as the surface ofthe window layer 110. The bent area filling portion 132 may completelycover the protrusions 114, but is not limited thereto, and when theprotrusions 114 is formed to have substantially the same height as thesurface of the window layer 110, a surface of the protrusions 114 can beexposed to the exterior of the surface of the bent area filling portion132 even after the bent area (BD) is filled by the bent area fillingportion 132.

Further, the flexible display panel 120 according to the presentexemplary embodiment can include a hard coating layer 130 formed on thewindow layer 110 and the bent area filling portion 132. In theembodiment of FIGS. 5 and 6, the hard coating layer 130 can be formed ofthe same material as the bent area filling portion 132. As describedabove, the material forming the hard coating layer 130 can be flexible.Accordingly, the bent area filling portion 132 of the present exemplaryembodiment can also be formed of the same material as the hard coatinglayer 130.

Since the bent area filling portion 132 is formed on an upper portion ofthe flexible display panel 120 corresponding to the emission area (LE),it can be formed of a transparent material including transparentsynthetic resins or glass. Accordingly, the hard coating layer 130 ofthe present exemplary embodiment can also be formed of a transparentmaterial.

As shown in FIGS. 7 and 8, a flexible display 100 in which the windowlayer 110 is partially removed so that a plurality of grooves 116 can beformed according to the third exemplary embodiment also includes awindow layer 110 and a flexible display panel 120 including a bent area(BD) and a non-bending area (FL). Since the window layer 110 and theflexible display panel 120 of the present exemplary embodimentcorrespond to those described above, a detailed description thereforwill be omitted.

In the embodiment of FIGS. 7 and 8, the bent area (BD) includes aplurality of grooves 116 formed by partially removing the window layer110. The grooves 116 are formed by partially removing the window layer110 to have a greater cross-section than that of the emission area (LE)of the flexible display panel 120. For example, as shown in FIGS. 7 and7, the width W1 of the grooves 116 can be greater than the width W2 ofthe emission areas (LE). When the cross-section of the grooves 116 aregreater than that of the emission area (LE), as in the present exemplaryembodiment, light emitted from the emission area (LE) can be directlyemitted to the exterior of the flexible display 100 without beingrefracted or dispersed, as in the second exemplary embodiment.Accordingly, even when the flexible display 100 is bent, its opticalcharacteristics can be preserved.

The grooves 116 of the present exemplary embodiment are formed removinga portion of the window layer 110 formed at a position corresponding tothe emission area (LE), but they are not limited thereto, and thegrooves 116 can be formed by partially removing the window layer 110 ina thickness direction of the window layer 110. The flexible display 100of the present exemplary embodiment can further include a hard coatinglayer 130 formed on the other surface of the window layer 110. Since thehard coating layer 130 of the present exemplary embodiment is formed onan upper portion of emission area (LE) of the flexible display panel120, as in the hard coating layer 130 of the second exemplaryembodiment, it can be formed of a transparent material includingtransparent synthetic resins or glass. The grooves 116 according to thepresent exemplary embodiment can be filled with the same material as thehard coating layer 130, so that the groove 116 becomes a filled groove134.

When the filled grooves 134 are filled with the same material as thehard coating layer 130, since refraction or dispersion of light emittedfrom the emission area (LE) can be prevented by an interface surfacebetween the filled grooves 134 and the hard coating layer 130, theoptical characteristics of the flexible display 100 of the presentexemplary embodiment can be maintained.

A flexible display 100 according to various exemplary embodiments hasbeen described. According to the various exemplary embodiments, evenwhen the flexible display 100 is bent, since stress due to the bendingcan be properly distributed, it is possible to prevent the flexibledisplay from being damaged and maintain the optical characteristicsthereof when being bent.

While the inventive technology has been described in connection withwhat is presently considered to be practical exemplary embodiments, itis to be understood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A flexible display, comprising: a window layerincluding a bending area and a non-bending area; and a flexible displaypanel formed over a surface of the window layer and configured todisplay images, wherein the bending area includes a plurality of cutportions which are configured to be at least partially separated along aplurality of cut lines formed therebetween.
 2. The flexible display ofclaim 1, further comprising: a hard coating layer formed over anothersurface of the window layer so as to oppose the flexible display panel;and an adhesive layer interposed between the window layer and the hardcoating layer, wherein an end of each of the cut portions is configuredto slip along a surface of the adhesive layer as the flexible display isbent.
 3. The flexible display of claim 2, wherein the ends of the cutportions are further configured to slip along the surface of theadhesive layer so as to be spaced apart from each other.
 4. The flexibledisplay of claim 1, wherein the flexible display panel includes: adisplay area including at least one pixel configured to emit light so asto display an image; and a non-display area, wherein the non-bendingarea is arranged at a position corresponding to the display area, andwherein the bent area is arranged at a position corresponding to thenon-display area.
 5. The flexible display of claim 1, wherein the cutportions are directly connected along the surface of the flexibledisplay panel.
 6. A flexible display, comprising: a window layerincluding a bending area and a non-bending area; and a flexible displaypanel formed over a surface of the window layer and including aplurality of emission areas configured to emit light to display animage, wherein at least a portion of the window layer is removed fromthe bent area.
 7. The flexible display of claim 6, wherein the bent areaincludes: a plurality of protrusions, each having a greatercross-section than that of the emission area, wherein the protrusionsare arranged at positions corresponding to the emission areas; and afiller formed over the protrusions such that the height of the bendingarea is substantially equal to that of the window layer.
 8. The flexibledisplay of claim 7, wherein the filler comprises transparent syntheticresins or glass.
 9. The flexible display of claim 8, further comprisinga hard coating layer formed of the same material as the filler andformed over another surface of the window layer so as to oppose theflexible display panel.
 10. The flexible display of claim 6, wherein thebent area includes a plurality of grooves arranged at positionscorresponding to the emission areas, wherein each of the grooves has across-section that is greater than that of the emission areas.
 11. Theflexible display of claim 10, further comprising a hard coating layerformed on another surface of the window layer so as to oppose theflexible display panel, wherein the hard coating layer is formed oftransparent synthetic resins or glass.
 12. The flexible display of claim11, wherein a filler comprising the same material as the hard coatinglayer fills in the grooves.